Generally, an IC device may include different types of components (e.g., transistors) that can provide different functionalities and have different applications. Also, an IC device can be designed to include planar type or fin-type components that may, for example, operate at different voltages, have different power consumptions, or provide different performances in a given application. For instance, a certain component in an IC may be part of a core module/section that may be designed to provide high performance and short channel effect (SCE) control at a given voltage or power consumption level. Another component may operate at a higher voltage and function as an interface (e.g., I/O) component. As a result, core components require a fin-type field-effect transistor (FinFET) structure, whereas I/O devices may be planar type devices. Although challenging, different types of components may be integrated into an IC device in order to meet application or industry demand. However, using the different manufacturing processes/structures requires extra steps and masks. Alternatively, using the FinFET structure for both means that they share the same bulk silicon, which engenders a bulk leakage concern for the I/O device.
FIG. 1 schematically illustrates a Si substrate that can be used to construct FinFET structures in an example IC device. Si substrate 101 includes Si fin regions 103 and 105, each of which may include a plurality of Si fins, wherein adjacent fins are separated by adjacent oxide regions 111. Additionally, the Si substrate 101 may include cavities filled with an oxide material to form shallow trench isolation (STI) regions 107 and 109. The Si fins may be utilized to construct FinFET structures while the STI regions provide protection against electrical current leakage between adjacent components in an IC device. In this example, the STI region 109 is a deeper STI, which may be formed post formation of an STI region (e.g., STI 107) by employing a similar process, where a deeper STI includes a thicker filling of oxide that extends to a deeper depth in the substrate 101. In integrating various types of components into a single IC device, for example, due to a three dimensional process flow used in FinFET technology, all components fabricated by the use of this technology utilize the FinFET structure. For example, an I/O device that would operate at a higher voltage (e.g., Vdd at gate) and have a thicker gate dielectric will be fabricated via the same process utilized in fabricating a core component that would be operating at a lower voltage with a shorter gate and a thinner gate dielectric. However, an I/O component does not require an advanced fabrication process and the SCE control due to its functionality. The I/O component may therefore be a planar type component, but as discussed, integrating planar and FinFET components may be challenging (e.g., additional process steps and masks). However, even if the two components were integrated in an IC device by using FinFET structures for both, the two components would share the same bulk (e.g., Si substrate) where bulk leakage current would be a concern for the I/O component.
A need therefore exists for a methodology for integrating I/O components into IC devices, with minimal additional process steps, and the resulting device.